Shuffle fixes and cleanup

add Joblogger to Spark (on new Spark code)

Optimize PySpark worker invocation

- Exclude a version of ASM 3.x that comes from HBase
- Don't use a special ASF repo for HBase
- Update SLF4J version
- Add sbt-dependency-graph plugin so we can easily find dependency trees

fix typo and coding style in #638

Conflicts:
	project/SparkBuild.scala

Add hBase example (retry of pull request #596)

Reduce ZippedPartitionsRDD's getPreferredLocations complexity from O(2^2n) to O(2^n)

Bug fix: Zero-length partitions result in NaN for overall mean & variance

SPARK-781: Log the temp directory path when Spark says "Failed to create temp directory."

Conflicts:
	core/src/main/scala/spark/scheduler/cluster/TaskSetManager.scala

temp directory".

Enhance pipe to support more features we can do in hadoop streaming